The discovery of intact remains of crocodile-like animals called phytosaurs came to light this week when researchers announced it at the Western Association of Vertebrate Paleontologists conference at Dixie State University in St. George, Utah. Based on an initial excavation, the 70-yard site “may be the densest area of Triassic period fossils in the nation, maybe the world,” Rob Gay, a contractor at the Museums of Western Colorado, said in a statement.
In an interview, Gay – who led a team of researchers on last year’s expedition – called it “the largest and most complete bone bed in the state of Utah, and one of, if not the largest, anywhere in the United States.” He called the discovery of three intact toothy, long-snouted fossils from the period extremely rare, adding that the “density of bone is as high or greater than all the other Triassic sites in the country.”
The fossil bed is part of the Chinle Formation, ancient river and flood plain deposits that run through the center of the original monument President Barack Obama designated in December 2016. But that sedimentary rock also contains uranium, which made it more commercially attractive than other parts of Bears Ears.
In December, The Washington Post reported that the firm Energy Fuels Resources lobbied Interior Department officials to shrink the boundaries of the monument, in part to allow the company greater access to areas where it held uranium mining rights. Trump’s Bears Ears proclamation, which took effect Feb. 2, cut more than 1 million acres from its original 1.35 million-acre expanse. A separate proclamation reduced another national monument in Utah, Grand Staircase-Escalante, by about 800,000 acres.
Other large Triassic-period fossil discoveries have been made in Texas, Arizona and New Mexico, so a find as far north as Utah is significant, Gay said. The Triassic period took place immediately after the first mass extinction on Earth, between 251 million and 199 million years ago, and phytosaurs evolved alongside other species that emerged after roughly 95 percent of the previous species had perished.
Phytosaurs are not considered dinosaurs, Gay said, but “seeing how these animals were able to live in northern parts of the continent might give us some idea of how dinosaurs were able to survive … and take over the world.”
The new find at Bears Ears underscores the fact that Utah is home to key paleontological deposits, and changes in national monuments there could effect the course of future scientific research. David Polly, president of the Society of Vertebrate Paleontology, said in an interview that 14 paleontologists are working on sites that used to be within Bears Ears’ boundaries but no longer have protection; twice as many are conducting research on sites that had lain within Grand Staircase-Escalante National Monument until earlier this month.
One of the reasons Grand Staircase-Escalante was first designated in 1996, for example, was because of its value as a paleontological site. Its Kaiparowits Plateau ranks as one of the most important examples of the Mesozoic Era, and Polly noted that it has “yielded 27 new species never been known to science before.”
But now nearly half of the Kaiparowits Plateau falls outside the new boundaries, Polly noted – including nearly all of the Tropic Shale, a roughly 94 million-year-old swath of rock that Trump’s monument proclamation identifies as a protected object. More broadly, Polly has identified 472 known scientifically important sites that now lie outside Grand Staircase-Escalante’s boundaries.
Polly said he is “most worried about” the Tropic Shale, because it contains commercially viable shale gas deposits and is accessible by road. If shale gas development took place there, “you would also be splintering all the fossils in it and erasing all the geochemical signals that tell us about the extinction, the chemistry of the time.”
Gay said he worked with conservationists and other groups on the bid to designate Bears Ears as a national monument because of its fossil deposits. He searched for Triassic-era fossils for three years before he came across the recent find in June 2016.
“We decided to stop at some exposures we found promising and found the fossils right away,” he said. Exposures are parts of cracked rock that can reveal fossils.
While the monument survived, the change in designation has an immediate effect on Gay’s work, he said, because he could no longer use part of a $25,000 Bureau of Land Management grant he was awarded to continue excavating the site.
“We were all really upset. We didn’t want to believe it at first,” Gay said, describing the team’s mood as Interior Secretary Ryan Zinke toured Bears Ears before recommending that it be reduced.
The Bureau of Land Management did not respond to requests for comment on Thursday.
Gay’s team has been nervous, in part, because it determined during the course of the research that the site had been looted. The team found plaster that had been made to encase a portion of a skull. Gay alerted the BLM’s district paleontologist to the problem, and a bureau official told him that its Arizona office had a fragment of fossil that was surrendered in 2008 by a collector who lacked a permit. The team matched the fossil to the recent Bears Ears findings, proving that it came from the same site.
“This may be one of the only times a recovered fossil has been traced all the way back to the location where it was looted,” Gay said.
“They broke off the skull,” Gay said of the amateurs who robbed the site. “They didn’t even take the whole skull. Also they missed the entire rest of the animal and several other animals laying on top of it and hundreds and hundreds of bones laying across the slope.”